Organic chemicals responsible for oviposition attraction of the mosquito Aedes triseriatus will be isolated from natural sources and identified. This will be accomplished by (a) extraction of representative hardwoods with a range of solvents; (b) testing chemical mixtures contained in these extracts for oviposition activity using a laboratory colony and comparing egg counts on test samples with those on distilled water references; (c) further fractionation of active extracts using solvent partitioning, acid-base separation and finally thin-layer chromatography, column chromatography and/or gas-liquids chromatography with activity being evaluated at each stage of separation; (d) structural identification of pure, active compounds using spectroscopic and chemical methods; and (e) field testing of oviposition activity.